This invention relates to a method of winding armatures for revolving-field electrical machines and more particularly to an improved winding method that permits a greater coil density to be obtained and avoids the likelihood of damaging the wire by the winding needle during the winding operation and also to an improved armature construction.
Various methods have been employed for forming the coil windings for the armature of rotating electrical machines such as motors or generators. Generally these winding methods result in somewhat complicated structures and structures wherein the maximum coil densities are not capable of being obtained. Several of these methods involved passing a needle in the slot between the extending cores of the armature and then having that needle circumscribe the individual cores so as to form the windings. Because of the fact that the needle must be passed in the space between the cores, room must be left for it and this decreases the coil density.
In addition, there is a likelihood that the needle may engage already wound coils and damage them particularly by removing their insulation. These various prior art methods are described in full detail in the co-pending application assigned to the Assignee hereof, entitled xe2x80x9cStator Coil Structure For Revolving-Field Electrical Machine and Method Of Manufacturing Samexe2x80x9d, App. No. 09/683764, filed Feb. 12, 2002.
Although the structure and method shown in that aforenoted co-pending application is very effective in achieving the goals set forth therein, it is believed that further improvements can be made. Thus it is a principle object of the invention to provide an improved winding method that can achieve the results set forth in the aforenoted co-pending application and at the same time the structure of the armature can be simplified and the winding technique improved so as to avoid any possible damages to the coils while being wound and to insure maximum coil density.
It also is a further object of this invention to provide an improved armature construction that provides dense coil windings with protection between the several layers of the individual windings.
A first feature of this invention is adapted to be embodied in a method of winding the coils of a rotating electrical machine. In this method, a circular core of magnetic material with a plurality of magnetic pole teeth extending radially from the circular core is provided. Each of the magnetic pole teeth defines a core and slots formed therebetween. Each of the slots defines a mouth that is formed between adjacent outer ends of the cores. The winding method comprises the steps of positioning a threading needle having an opening through which the wire for the winding of the coils is fed into proximity to one of the mouths. The needle opening is moved in a path around one of the pole teeth without moving the needle in any substantial distance into the slot to form a first winding. During the winding of successive coils the needle is moved in a generally circular path of greater length than the final length of the coil winding to provide slack in the length of the wire.
Another feature of the invention is also adapted to be embodied in a method of winding the coils of a rotating electrical machine. In accordance with this method, a circular core of magnetic material with a plurality of magnetic pole teeth extending radially from the circular core is also provided. Each of the magnetic pole teeth defines a core and slots formed therebetween. This winding method comprises the steps of positioning a threading needle having an opening through which the wire for the winding of the coils is fed into proximity to each of the pole teeth and moving the needle in a path around the pole teeth to establish at least a first winding layer around the pole tooth. Then a thin insulating layer is positioned over the at least first winding layer and a further winding layer is placed over the insulating layer.
A further feature of the invention is also adapted to be the coil windings for the armature of a rotating electrical machine. The armature comprises a circular core of magnetic material with a plurality of magnetic pole teeth extending radially from the circular core. Several layers of coil windings are formed on each of the magnetic pole teeth. At least one thin insulating layer is positioned between adjacent of the coil windings.